Trivia

Dog

Valve development commentary in the game mentions that players seemed to love Dog, so they made him the first thing the player sees at the start of the episode.

Dr. Breen

Apparently, some citizens enjoyed some of the Breencasts. In the game, one citizen can be heard saying to another; "I don't miss Dr. Breen, but I do miss his show. Remember when he had the jugglers on?". This is possibly a reference to the satirical webcomic Concerned (the author of Concerned, however, denies this, believing it to be something of a stretch and citing the absence of jugglers in his strip).

German version

There are changes in some German versions of the game:

All blood by humans (including German Freeman) and blood which is part of the level design was coloured green

Almost all enemies instantly disappear after being killed. An exception are some dark parts were burning zombies are used as light source.

The cries of burning zombies were toned down

During the part were Alyx finds the first zombine, the corpse she refers to was removed